newbie & piston rings/ big end shells

[andyroach]

Hi all, just thought I would introduce myself to you all.
My names Andy, Live in the south of Spain own a T3 guzzi, 501 camel, xs 650 and a load of other bikes in various states of disrepair.
I am also in the process of building a 3 1/2 sport with a 500 motor to compete in the coming years race series over here.
I also own a 3 1/2 excaliber, the remains of a late model camel and the remains of a new york, which I will be selling off in bits to fund said race bike.
I am looking for some piston rings for a 501 and also I have heard of a conversion to rollers for the big end from shells. is it a recognised mod?
Any help is greatly appreciated.
Andy

[andyroach]

I have been looking through the older posts and found that maybe I misunderstood the person I was talking to about the big end shells/roller bearings. I think he may have been talking about the mains?
Andy

[morini_tom]

Hi Andy,

Yes the roller conversion is for the alternator side main bearing (which as standard is a plain shell mounted in a carrier which bolts into the cases. You need no crankcase mods for this other than to plug the 3 bolt holes (I had mine welded up) and then you get the crank ground to suit.

I wouldn't tear an engine down just for this mod but it's worth doing while you're in there. Both my 501 motors have this bearing and they have given no problems despite quite some abuse!

I don't know of a source for piston rings I'm afraid. I'd try NLM as a first port of call unless anyone knows of a source in mainland europe?

[andyroach]

Hi Tom,
NLM don't have piston rings and I have given Stuart a couple of numbers for companies that supplie them (one has 4 million different types of piston rings, which I thought was quite a lot).
Do you know the number of the bearing that fits the crank? I did find the thread with this conversion in it, but can't seem to find it anymore.
I may have found some pistons/barrells and rings in germany, but will have to see if it will put my wallet in to intensive care. I suspect it won't be cheap.
Does anyone have any experience of a shop called ducati developments(I think they are in the links on this site)?
Max, who I spoke to seemed helpful and seemed to have a lot of Morini bits.
Cheers
Andy

[ian scott]

Hello Andy,

Did you find rings for your 500?

I am on the same search.

Cheers. Ian.

[andyroach]

Hi Ian,
No I didn't find any piston rings, but I was talking to Alex at NLM a couple of days ago and he said that they have just had a sample batch in from a supplier and he will be testing them out. In retro spect we where talking about the 500's, but I am pretty sure that Stuart also said that he was having the 501 rings made by the same company.
Talk to Stuart. He's bound to make more sense than I do.
Best of luck with the search.
Andy

[Harry]

With regards to piston rings, then you could use any oversize that are available as long as you set the ring gap to the bore. If you cannot get any then try Omega pistons in Blackheath nr B'Ham as they made the rings to suit the forged pistons they made for me. I know people have been to them for one offs in the past.
Big end shells, the shells from the FIAT Multipla of the sixties are the same diameter with the addition of being slightly wider so reduces the loading on the bearing, the keep has to be modified on the shells. I have a number of sizes for spares for my own bikes and as pairs they cost a quarter of the Morini dedicated ones. I fitted these to a 507cc engine I rebuilt for a chap with one big end having run on steel to steel. When you build up your motor make sure the crank pin is cleaned out as the oil holes become blocked owing to the centrifugal seperation of the crud and subsequent build up and closing off the holes, which is why I fit external full flow oil filters to my engines. I got my bearings from Piston Broke in Bristol on the advice of Ade Crimp.

[EVguru]

With regards to piston rings, then you could use any oversize that are available as long as you set the ring gap to the bore.

If you just want to keep an engine running then that works. If you want best performance, then it's a poor solution.

Rings are compressed in a fixture and ground circular at their designed bore size. Fitting them to a smaller bore means they are no longer precicely circular. It's possible to re-temper and re-grind rings, but better to find ones the right size.

[Steve Brown]

I can't remember where I heard about them, but I recently used a firm called Cox and Turner. They stock all sorts of rings and other engine bits and will also have rings made for you, if all else fails. They were more than helpfull and very knowledgeable when I needed help for my matchless.
You will need to give them the bore size, the depth and the width of the rings you need, and if you are using an iron or plated cylinder bore. They will do the rest. They were good value too and very quickly supplied.
They have two addresses, the phones for each are; 01425 652627 and 01935 826816.

website; www.coxnturner.freeserve.co.uk

email; info@coxandturner.co.uk

Hope that helps, well worth a try in my opinion-and no I'm not connected, just a satisfied customer.

Steve.

[andyroach]

Well thats given me a couple of avanues to go down. I am trying to work out what the biggest piston is that I can fit in to the 350 iron barrels, without changing the cylinder sleeve. Anyone had a go at this? So far all I have come up with is the 370cc pistons from NLM. I was looking in to fitting a set of guzzi V50 pistons, but have run out of time at the moment for any motorcycling tom foolery (preparing the house for sale).
Cheers
Andy

[EVguru]

Came across this a while back;

http://www.kevinbreedonracing.co.uk/pro ... inders.asp

[mgill]

I was looking in to fitting a set of guzzi V50 pistons

The V50 pistons are 74mm... that's wider than the O.D. of the 350 liner.
V50-1 were chromed barrell and V50-II+III were Nigusil plated.

V35 Pistons on the other hand were only 66mm.(still with plated barrells)

I think the early ones (series1) were cast pistons and the later (series II+III)
were forged.

Hope that answers some of your questions...
(these things keep me awake at night too )
Mathew

[andyroach]

Thanks Mathew,
I am wondering if I could get a set of 501 barrels bored to 74mm (from 71mm) get them re-nicasiled, then use a V50 piston? I could machine down the barrels to fit the piston/stroke hight before I had them Nicasiled (there is a company in Birmingham or wolverhampton).
It isn't going to happen at the moment as I am trying to finish the house to get it on the market, but for the future or if anyone else is interested it's an idea.
Andy

[EVguru]

Why not put alloy liners into 350 barrels and have them Nikasiled?

[mgill]

Why not put alloy liners into 350 barrels and have them Nikasiled?

I was thinking of a 550, same-ish bore/stroke ratio as the stock 350.
The 74mm bore with 350 crank...
well then again, like you said, why not?